## 0.7. About the Second Edition

The first edition of this book covered the 1988 version of the Korn shell. Shortly after it was published, David Korn released the 1993 version, which included compatibility with the POSIX 1003.2 shell standard, as well as many new features.

Although ksh93 has been slow to spread to the commercial Unix world, source code is now available, so anyone who wants a copy of the latest and greatest version of ksh93 has but to download the source and compile it. With this in mind, we have made ksh93 the focus of the second edition, with a summary of the differences available in an appendix. This edition covers the most recent ksh93 release available at the time of writing, which includes some significant features not found in earlier versions.

The basic structure and flow of the book remains the same, although we have fixed a number of mistakes and typos in the first edition and updated kshdb, the Korn Shell Debugger, to work with ksh93. Appendix A now includes more information about Korn shell work-alikes, both for Unix and Windows systems.

Also included with this edition is a reference card that covers many of the features of ksh93 described in this book. This card is copyrighted by Specialized Systems Consultants, Inc. (SSC), and is reprinted by permission. SSC sells a four-color, 26-panel, 3.5-inch by 8.5-inch version of the card that covers both ksh88 and ksh93 in considerably more detail. See http://www.ssc.com for more information.

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